feat: 重构为 Monorepo 架构并实现 HTTP Server

架构变更:
- 采用 pnpm workspaces 实现 Monorepo 结构
- 将现有代码迁移到 packages/core
- 新增 packages/server HTTP 服务层

Server 功能:
- REST API: 会话管理、工具管理、配置管理
- WebSocket: 实时双向通信支持
- SSE: 服务端事件推送
- Hono + Bun 作为运行时

API 端点:
- GET/POST /api/sessions - 会话 CRUD
- GET/POST /api/sessions/:id/messages - 消息管理
- GET /api/sessions/:id/events - SSE 事件流
- WS /api/ws/:sessionId - WebSocket 连接
- GET/POST /api/tools - 工具管理
- GET/PUT /api/config - 配置管理

packages/core/src/tools/load_description.ts

@@ -0,0 +1,55 @@
+import * as fs from 'fs';
+import * as path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+// 工具名到子目录的映射
+const TOOL_CATEGORY_MAP: Record<string, string> = {
+  // shell
+  bash: 'shell',
+  // filesystem
+  read_file: 'filesystem',
+  write_file: 'filesystem',
+  edit_file: 'filesystem',
+  multi_edit: 'filesystem',
+  list_directory: 'filesystem',
+  create_directory: 'filesystem',
+  search_files: 'filesystem',
+  grep_content: 'filesystem',
+  get_file_info: 'filesystem',
+  move_file: 'filesystem',
+  copy_file: 'filesystem',
+  delete_file: 'filesystem',
+  // web
+  web_search: 'web',
+  web_extract: 'web',
+  // git
+  git_status: 'git',
+  git_diff: 'git',
+  git_log: 'git',
+  git_branch: 'git',
+  git_add: 'git',
+  git_commit: 'git',
+  git_push: 'git',
+  git_pull: 'git',
+  git_checkout: 'git',
+  git_stash: 'git',
+  // todo
+  todo_read: 'todo',
+  todo_write: 'todo',
+};
+
+export function loadDescription(toolName: string): string {
+  const category = TOOL_CATEGORY_MAP[toolName];
+  const filePath = category
+    ? path.join(__dirname, 'descriptions', category, `${toolName}.txt`)
+    : path.join(__dirname, 'descriptions', `${toolName}.txt`);
+
+  try {
+    return fs.readFileSync(filePath, 'utf-8').trim();
+  } catch {
+    throw new Error(`无法加载工具描述文件: ${filePath}`);
+  }
+}